THIS took a change in structure and tactics to pull off and, for this game, it worked for North Ballarat Roosters.

In the end, it was a resounding 40-point victory against Carlton's Northern Blues and in the process, it boosted the Selkirk Roosters back into the Victorian Football League top eight.

But there was always that threat the Blues could steal this game away at Eureka Stadium on Sunday.

The Roosters kept working to capture the important win without key forwards Jordan Staley (ankle) and Michael Searl (general soreness), both late withdrawals ahead of the game.

So, the Roosters looked to how to best use imposing ruckman Eric Wallace up forward with Bryce Curnow to maintain a towering presence near the goal face.

Ballarat Swans' ruck Sam Conroy was called up late Friday, once Staley was ruled out, and formed an effective tag-team with Wallace on the in-form Blues' tap man Cameron Wood.

Conroy offered fresh legs on the ball and in following Wood, who is dangerous up forward, and freeing Wallace to spend more time forward.

Roosters' coach Gerard FitzGerald said this was a debut tactic for the team, and one they might never use again - but it was right for this game.

"Sometimes out of necessity you come up with good strategy thinking and this worked for this game," FitzGerald said.

"I admire the role Sam Conroy played...he's become fitter the past few week and was ready to grab his opportunity."

The Roosters were forced to keep adapting across the field under the Blues' persistence.

Even though the Blues kicked two opening goals, the Roosters dominated the first quarter.

Only, both teams were struggling to convert - Rooster Max Warren broke a 19-minute goal drought in the second term.

Play was a free-flowing spectacle. The lack of goals did not do the battle justice.

The Roosters pummelled the Blues in 10-goal to five second half. Curnow kicked his entire four-goal haul in the third quarter.

They were moving the ball better through the centre and up forward and even though the Roosters held a four-goal lead at the final break, the Blues took momentum into the final term with a booming goal on the siren.

Rooster Luke Kiel moved into his trademark lock-down mode, moving on to dangerous young Blue Daniel Watson late in the third and restricting him to four touches in the fourth. Watson had eight touches in the third and was adding spark up forward before Kiel stepped in to shut him down.

The Blues' inaccuracy and ill-discipline started to prove costly.

Roosters' coach Gerard FitzGerald reminded his players at the final huddle that the Blues wanted to win as much as the Roosters.

The Roosters stamped their intentions, via a strong Nick Couch mark and goal, about one minute into the final term, keeping the Blues at bay.

This has been a long, important phase for the Roosters - seven games between breaks - and they have one assignment, Bendigo in Ballarat, to go before preparing for a final push to finals.